In this HMO system-level randomized controlled effectiveness trial, we will evaluate the feasibility, effectiveness, cost-effectiveness, and sustainability of an innovative and practical team approach for delivering smoking cessation assistance to interested smokers in a large dental HMO. We, and others, have demonstrated the efficacy of the 5A model in medical and dental settings. Progress has been made nationally in implementing and maintaining the Ask and Advise components of the 5A model in routine practice, but less progress has been made with the Assist and Arrange components, particularly in dental practice. Barriers to implementation are significant. More practical and innovative approaches are needed that minimize demands on staff, yet take advantage of the "teachable moment" created by the clinical encounter to encourage more patients to access and use convenient cessation support services. Chart reviews show that KP dentists and hygienists currently provide simple advice to almost all smokers, but do not provide cessation assistance. In this study, dentists and hygienists in half of 14 large facilities will be trained to connect tobacco users by phone to a professionally staffed tobacco quitline as a part of the dental visit. If patients prefer, quitline staff will call them at a more convenient time. Quitline staff will provide brief counseling and assessment and a full menu of cessation services, including multi-session telephone and face-to-face programs and medications. This Active Referral strategy is both practical and innovative, as it takes advantage of available resources; efficiently distributes intervention activities between dentists, hygienists, and counseling specialists; and could be delivered in individual, small, or large dental practices. Service delivery and one-year cessation outcomes will be assessed for randomly selected treatment and control patients (n--2,800) with dental exam visits either early or later in the implementation period. The large size of the KP dental plan (160,000 members) makes it feasible to evaluate the proposed approach. The findings will be generalizable because the practice style and visit flow for staff is similar to other practice settings, and telephone-based quitline services are widely available through state-run quitlines.